I may have to refrain from posting until I get my pinion angle measured...

What should the stock angle be?

 

East87 and Timmbo, one of you need to change your sig picture, I keep getting you guys confused!!

 

I ordered a driveshaft from Shaftmasters today. If I am impressed with it, I will be ordering 12 more from them. I will post my results after the install.

The stock pinion angle on a non-lowered car is about -1 degree.

 

i have the direct bolt in shaftmasters driveshaft and love it! rolled it to 85mph and its smooth as glass.

 

Well I pushed it to 90-ish briefly only because my car is a cop magnet with the reflective red stripes in the sunlight LOL! I'm more of a 0-60 junkie. Anyway I didn't notice a vibration coming from the shaft per se but it seems to be a VERY good conductor of resonant sounds at high speeds. With the 4.10s spinning higher rpms at higher highway speeds combined with the headers, O/R H and Borla Stingers I was getting a much more pronounced reverberation of noise that might be confused with vibration. Vibration to me being the physical shaking of the car as opposed to what I was really feeling which was the sound resonance of all my mods getting channeled through that uninsulated one piece shaft as well as tire and road noise. I guess you could compare what I felt around 90mph to how a car stereo without massive subs going cranked up very loud will penetrate you but not necessarily physically shake you. It makes perfect sense what Dave was saying about the reasons for the Ford two piece design that it is also insulated to mask vibrations. Its just an all speeds all purpose shaft considering the design of the car. I can say I haven't hit over 100 mph yet to test further. Too much traffic around most of the time to get away with it.

I think your concerns are valid and I know Dave at Shaftmasters will take care of you. Like I said before you just have to weigh things out like what speed you spend the majority or your time driving and is it at those speeds where you find the shaft acceptable. I truly believe there are compromises to be made here considering the one piece aftermarket design when actually the car was engineered for a two piece for a good reason I'm sure. Obviously a one piece is much cheaper than a two piece with cv joints and a center bearing. And you know Ford as well as other manufacturers like to cut cost where they can. So you know Ford required the use of the more expensive two piece design to solve and angle problem or reasonant sound wave problem at all rpms at all speeds. I'm no engineer but it makes sense.

 

YES! The high-speed vibration/noise is like a loudly buzzing woofer!...I can feel it in my seat and the pedals as well though. Would you say that was the case with you?

 

Yep. But it's not too bad. I can comfortably say though that I rarely if ever hit 90+ mph so it's really not an issue for me because at 80mph and below where I drive just about all the time its perfect.

 

You guys should try taking a sixties muscle car over 100. You think these things get loud and vibrate?

Yikes.

 

Interesting. I'm sure the number of shaft rotations at 85 mph plays some part in all this.

i run 235/50/18s stock. the circumference of my tire is approximately 86.08 inches. @ 85 mph, i'm going approximately 1496 inches per second which means the tires are making complete revolutions at a rate of 17.38 per second. multiply that by 4.10, and you get driveshaft rotations per second at about 71.26...4275.6 driveshaft rotations per minute. that's a lot...It really kinda puts things in perspective a bit. Even assuming that the driveshaft is completely balanced to spec (as I have believed all along), the tolerances are extremely low for all the other components of the rear suspension as well as the FRPP rear gears.

I dropped it in 4th gear on the highway to make a pass and WOW did it go! It just GOES...I was extremely impressed.

 

Same here. I get a buzzing/vibration at 80+. Its more pronounced at decelleration. It is almost like hitting the wake up strip on the highway.